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30 June 2016 to 1 July 2016
Other Institutes
Europe/Zurich timezone

Spectral Imaging using Hybrid Integrated, Large-Area High Resolution X-ray Detectors

Not scheduled
10m
Auditorium & Conference Room (Other Institutes)

Auditorium & Conference Room

Other Institutes

ESADE Business School, Avenida Pedralbes, 60-62, 08034 Barcelona, Spain.

Speaker

Dr Ruud Vullers (Teledyne DALSA)

Description

In the commercial market, digital radiography is largely “charge integration” based, which results in a read noise that is composed of the quantum-limited photon shot noise, but also of electronic read noise and excess noise due to the non-reproducible charge packet sizes per absorbed X-ray photon. In X-ray imaging, as in other imaging domains, the ultimate sensitivity and signal-to-noise ratio are obtained when each incoming photon is counted - the so called quantum limit.
By this technique, significantly better image contrast can be achieved due to enhanced signal to- noise ratio. Also, since one can discriminate between energies and weight the contribution of each individual energy or each energy range to a final image, significant enhancement in image quality while reducing the radiation dose is and has already been shown to be possible. Other important advantages of the photon counting technique include the improvement of spatial resolution, the reduction of noise for the same quantum efficiency, and the ability to yield reconstructions with reduced beam-hardening and reduced ghosting artifacts due to lag providing the potential for single-exposure multiple-energy imaging.
The technology has numerous societal benefits. For medical application, this means that patient examinations can be done quicker, sharper images can be obtained and lower doses can be used. By additionally measuring the energy of the incoming photons, the energy information will enable tissue or material identification: Applications range from medical diagnostics, bone densitometry and mammography. Also Security applications can benefit by additional means to identify dangerous or forbidden substances hidden in closed containers, suitcases and bags.

In the last decades a considerable effort in the scientific field has been devoted to the development of active pixel devices for the detection of X-rays. Examples of such devices are the Medipix2 and Timepix ASICs. The size of these detectors is still in the 1-2 cm2 range, with typical 256x256 pixels. These developments have benefited from the advance of the hybrid integration technologies developed for the IC industry.

In order for these devices to become commercially interesting for a wide range of applications and (currently unserved) markets, R&D needs to be devoted to the following basic elements:

  1. Increase detector Size: Applications call for several tens of cm2 (detector size up to 8 and 12 inch), a considerable increase from current devices. At the same time, yield of the combined ASIC/pixel stack needs to be addressed, in order to reach the 80 to 90% for complete stacks. Alternative architectures (both for design as for assembly) need to be developed.
  2. Reduce Cost Considerably. An issue directly linked to the size of the detector, as well as the yield. Furthermore, assembly technologies tailored for large areas and (new) hybrid device architectures need to be developed and optimized and processing cost needs to be reduced. 3D printing is also potentially beneficial for packaging elements.
  3. Improve Scintillators. Large area scintillators need to be developed with a high light yield, small decay times and high stopping power.

Our expertise is in the design and development of active CMOS detectors for large area detectors. Also, we have expertise in hybrid wafer to wafer technologies. By cooperating with various R&D partners in the different fields, we want to use our capabilities to build prototypes of energy resolved X-ray imaging and evaluate them in clinical tests, as well as in security trials.

Summary

Digital radiography will greatly benefit from a change from “charge integration” to phonton counting technology. The advantages are numerous:
Better image contrast can be achieved, significant enhancement in image quality while reducing the radiation dose, improvement of spatial resolution, reduction of noise for the same quantum efficiency, and the ability to yield reconstructions with reduced beam-hardening and reduced ghosting artifacts
For medical application, patient examinations can be done quicker, sharper images can be obtained and lower doses can be used. By additionally measuring the energy of the incoming photons, the energy information will enable tissue or material identification: Applications range from medical diagnostics, bone densitometry and mammography. Also Security applications can benefit by additional means to identify dangerous or forbidden substances hidden in closed containers, suitcases and bags.

In the last decades a considerable effort in the scientific field has been devoted to the development of active pixel devices for the detection of X-rays, like Medipix2 and Timepix ASICs. The size of these detectors is still in the 1-2 cm2 range, with typical 256x256 pixels. In order for these devices to become commercially interesting for a wide range of applications and markets, R&D needs to be devoted to increase size (large size detectors on 8 to 12 inch wafers while still obtaining large yields), reduce cost (related to size and yield) and improvement of Scintillators.
Our expertise is in the design and development of active CMOS detectors for large area detectors. Also, we have expertise in hybrid wafer to wafer technologies. By cooperating with various R&D partners in the different fields, we want to use our capabilities to build prototypes of energy resolved X-ray imaging and evaluate them in clinical tests, as well as in security trials.

Primary author

Dr Ruud Vullers (Teledyne DALSA)

Co-authors

Dr Inge Peters (Teledyne DALSA) Mr Jan Bosiers (Teledyne DALSA)

Presentation Materials

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